The subject matter disclosed herein relates to a transition piece aft frame and, more particularly, to a transition piece aft frame of a turbomachine to provide circumferential direct fuel injection with relatively low residence time.
A turbomachine, such as a gas engine turbine, generally includes a compressor to compress inlet gases, a combustor, which is fluidly coupled to and disposed downstream from the compressor section, and a turbine. The combustor has an interior in which the compressed gases are combusted along with fuel and includes a transition piece, which is formed to define an interior through which a main flow of products of the combustion flow toward the turbine. The turbine is fluidly coupled to the combustor downstream from the transition piece and thereby configured to be receptive of the main flow from the interior of the transition piece. As the main flow proceeds through the turbine, the energy of the main flow is converted into mechanical energy that is used to generate power and/or electricity. The main flow is eventually exhausted from the turbine and partially emitted into the atmosphere.
Due to the combustion of the compressed gases and the fuel, some of the emissions include pollutants, such as oxides of nitrogen (NOx). Recently, efforts have been undertaken to reduce the emissions of those pollutants. For example, late lean injection (LLI) of fuel into the combustor and/or the transition piece has been shown to provide for reductions in the emissions of NOx.